Synthesis and characterization of thermally rearranged (TR) polybenzoxazoles: Influence of isomeric structure on gas transport properties

Article abstract of DOI:10.1016/j.polymer.2015.07.024

Isomeric polyhydroxyimides based on 3,3′-diamino-4,4′-dihydroxybiphenyl (m-HAB) or 3,3′-dihydroxy-4,4′-diaminobiphenyl (p-HAB) with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) were prepared via an ester-acid monomer. The polyhydroxyimides were then acetylated using acetic anhydride to change the ortho-functional groups on the polymer chains. These ortho-functional polyimides were used as precursors for thermal rearrangement (TR) to polybenzoxazoles for gas separation membranes. The permeability coefficients of TR polymers significantly improved as the ortho-functional polyimides converted to polybenzoxazoles. The influence of meta and para isomeric monomers on the gas transport properties of the resulting TR polybenzoxazoles were studied. In addition, gas permeation properties show a dependency on the size of the ortho-functionality of the polyimide precursors.

Full text of DOI:10.1016/j.polymer.2015.07.024

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Accepted Manuscript
Synthesis and Characterization of Thermally Rearranged (TR) Polybenzoxazoles:
Influence of isomeric structure on gas transport properties
Hailun Borjigin, Qiang Liu, Wenrui Zhang, Kyle Gaines, Judy S. Riffle, Donald R.
Paul, Benny D. Freeman, James E. McGrath
PII:
S0032-3861(15)30105-1
10.1016/j.polymer.2015.07.024
JPOL 17984
DOI:
Reference:
To appear in: Polymer
Received Date: 8 May 2015
Revised Date: 14 July 2015
Accepted Date: 15 July 2015
Please cite this article as: Borjigin H, Liu Q, Zhang W, Gaines K, Riffle JS, Paul DR, Freeman BD,
McGrath JE, Synthesis and Characterization of Thermally Rearranged (TR) Polybenzoxazoles: Influence
of isomeric structure on gas transport properties, Polymer (2015), doi: 10.1016/j.polymer.2015.07.024.
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ACCEPTED MANUSCRIPT

Evaluation Only. Created with Aspose.PDF. Copyright 2002-2021 Aspose Pty Ltd.
ACCEPTED MANUSCRIPT
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Synthesis and Characterization of Thermally Rearranged (TR) Polybenzoxazoles:
Influence of isomeric structure on gas transport properties
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Hailun Borjigin,1 Qiang Liu,2 Wenrui Zhang,1 Kyle Gaines,1 Judy S. Riffle,1* Donald R. Paul,2
Benny D. Freeman2 and James E. McGrath1
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1Department of Chemistry, Macromolecules and Interfaces Institute, Virginia Tech,
Blacksburg, VA 24061, USA
2Department of Chemical Engineering, Texas Materials Institute, Center for Energy and
Environmental Research, The University of Texas at Austin, 10100 Burnet Road, Bldg. 133,
Austin, TX 78758, USA
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Abstract
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Isomeric polyhydroxyimides based on 3,3’-diamino-4,4’-dihydroxybiphenyl (m-HAB) or 3,3’-
dihydroxy-4,4’-diaminobiphenyl (p-HAB) with 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane
dianhydride (6FDA) were prepared via an ester-acid monomer. The polyhydroxyimides were
then acetylated using acetic anhydride to change the ortho-functional groups on the polymer
chains. These ortho-functional polyimides were used as precursors for thermal rearrangement
(TR) to polybenzoxazoles for gas separation membranes. The permeability coefficients of TR
polymers significantly improved as the ortho-functional polyimides converted to
polybenzoxazoles. The influence of meta and para isomeric monomers on the gas transport
properties of the resulting TR polybenzoxazoles were studied. In addition, gas permeation
properties show a dependency on the size of the ortho-functionality of the polyimide precursors.
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